Longitudinal changes in epigenetic clocks predict survival in the InCHIANTI cohort

Why it matters

Most epigenetic-clock studies take one blood sample and ask whether a high biological age predicts later illness. But aging is a process, and the most useful measure may be how quickly the clock moves over time. If repeated measurements add information, they could become the way to track whether a lifestyle change or a drug is actually slowing aging. This study is one of the longest tests of that idea. Trials of anti-aging treatments need outcomes that change within a few years, long before people get sick or die. A clock whose rate of change predicts survival is a candidate for that role, which is why repeated-measurement studies like this one matter for the whole field.

What they did

The researchers studied 699 adults from the InCHIANTI cohort in Italy, followed for up to 24 years, with DNA methylation measured more than once. They calculated how fast several clocks (first-, second- and third-generation) accelerated over time and tested whether that rate was linked to death. Their models accounted for baseline epigenetic age and other confounding factors.

What they found

Faster increases in several clocks were robustly linked to a higher risk of death, even after accounting for each person's starting epigenetic age and other factors. In other words, the change over time carried information that a single measurement did not. The authors conclude that changes in epigenetic aging reflect a person's evolving health and may be sensitive indicators for testing interventions meant to extend healthspan and lifespan.

Limits

The cohort is fairly small (699 people) and comes from one region of Italy, so the results may not apply everywhere. The study is observational: it shows that a speeding clock predicts death, not that slowing the clock would prevent it. The abstract does not say which clocks performed best; the authors discuss strengths and limitations in the full paper. For an individual, a single commercial clock result says little; this study's point is that the trend across repeated tests carries the signal, and it does not show that any particular action will change that trend.

Key terms

Longitudinal study

A study that measures the same people repeatedly over time.

Epigenetic age acceleration

Biological age, as measured by a clock, running ahead of calendar age.

Cohort

A defined group of people followed over time.

Confounder

Another factor that could explain a link, such as smoking or illness.

Healthspan

The years of life spent in good health.

Mortality

Death from any cause during the follow-up period.

Biomarker

A measurable sign in the body, such as a blood test, that reflects a biological state.